U.S. patent number 7,685,854 [Application Number 12/011,789] was granted by the patent office on 2010-03-30 for axial spring balancing pin tumbler lock.
Invention is credited to Daniel Xu, Forrest Xu.
United States Patent |
7,685,854 |
Xu , et al. |
March 30, 2010 |
Axial spring balancing pin tumbler lock
Abstract
An axial spring balancing pin tumbler lock includes a
cylindrical shell, a plug rotationally disposed within the shell
and rotatable by a tubular key. The shell contains a plurality of
first pin bores annularly and evenly defined to the axis of the
shell for receiving first pins and first springs. The plug has a
through aperture for engaging with a elongated spindle, a key bore
coaxially defined on front end for receiving the tubular key, a
plurality of third pin bores annularly and evenly defined on front
end with same depth of the key bore for receiving third pins, and a
plurality of second pin bores defined on rear end of the plug for
receiving second pins and second springs. Each second pin may
contacts the tubular key and one of third pins simultaneously. The
extension force of the second spring at its preloaded length is
stronger than that of the first spring at its fully loaded length
so both second pin and third pin are urged by compound extension
force to their most extended position while the first pin is at its
most retracted position. The extended third pins bridge the shear
plane of the lock, the plug is then blocked from rotating. Since
the third pins are isolated from the opening keyway and are not
driven by key notches or external force directly, the conventional
lock picking or bumping methods must fail.
Inventors: |
Xu; Forrest (West Covina,
CA), Xu; Daniel (West Covina, CA) |
Family
ID: |
40897852 |
Appl.
No.: |
12/011,789 |
Filed: |
January 30, 2008 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20090188287 A1 |
Jul 30, 2009 |
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Current U.S.
Class: |
70/491; 70/419;
70/404 |
Current CPC
Class: |
E05B
15/06 (20130101); E05B 27/083 (20130101); Y10T
70/7565 (20150401); E05B 27/0057 (20130101); Y10T
70/7932 (20150401); E05B 2015/0448 (20130101); Y10T
70/7593 (20150401); Y10T 70/7853 (20150401) |
Current International
Class: |
E05B
27/08 (20060101) |
Field of
Search: |
;70/403,404,419,491,496 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Gall; Lloyd A
Claims
We claim:
1. An axial spring balancing pin tumbler lock comprising: a shell
having a through hole, a main bore defined on the rear end and a
plurality of first pin bores defined annularly and evenly on the
bottom surface of the main bore; a plug having a through aperture
and a key bore coaxially defined on the front end, whereas a
plurality of third pin bores being defined on the front end with
same depth of the key bore and arranged such that each one of the
third pin bores extends coaxially with one of corresponding first
pin bores in the shell; whereas a plurality of second pin bores
being defined annularly and evenly on the rear end and arranged
such that each one of the second pin bores is radially and inwardly
eccentric to its corresponding third pin bore; whereas each one of
the second pin bores radially and axially overlapping the key bore
and one of the corresponding third pin bores simultaneously;
whereas the plug being disposed into the main bore of the shell; a
spindle having a short axial groove defined on the front end and
being fixedly engaged with the through aperture in the plug; a
plurality of first coiled compression springs and first pins being
disposed into the first pin bores in the shell; a plurality of
second pins and second coiled compression springs being disposed
into the second pin bores in the plug; a plurality of third pins
being disposed into the third pin bores in the plug.
2. The axial spring balancing pin tumbler lock according to claim 1
wherein the second pin bores are greater than the third pin bores
in diameter.
3. The axial spring balancing pin tumbler lock according to claim 1
wherein the second pins is greater than the third pins in
diameter.
4. The axial spring balancing pin tumbler lock according to claim 1
wherein the extension force of the second coiled compression
springs at their preloaded length being stronger than the extension
force of the first coiled compression springs at their fully loaded
length.
5. The axial spring balancing pin tumbler lock according to claim 1
wherein an annular collar coaxially defined on the front end of the
plug mates a shallow bore coaxially defined on the bottom surface
of the main bore in the shell so to prevent the third pins from
being accessed by a picking tool.
6. The axial spring balancing pin tumbler lock according to claim 1
wherein the length of the third pins varies that the shortest is
such long that its front end is flush to the front end of the plug
when it is at its most extended position and the longest is such
long that its front end is flush to the front end of the plug when
it is at its most retracted position.
7. The axial spring balancing pin tumbler lock according to claim 1
wherein the shell further comprises a first annular groove defined
on the through hole approximate to the front end, a second annular
groove defined on the main bore near the rear end and a keyway
defined on the front end communicating to the first annular
groove.
8. The axial spring balancing pin tumbler lock according to claim 1
wherein a cover being fixedly attached to the spindle and abutted
against the rear end of the plug so to retain the second pins and
second coiled compression springs within the second pin bores in
the plug.
9. The axial spring balancing pin tumbler lock according to claim 7
wherein a internal retaining ring is disposed into the second
annular groove to prevent the plug from moving outwardly.
Description
FILED OF THE INVENTION
The present invention relates to a locking device. More
specifically, the present invention relates to an axial pin tumbler
lock with unique pick-resistant mechanism that can not be easily
unlocked by conventional lock picking or bumping approaches.
BACKGROUND OF THE INVENTION
The axial pin tumbler locks, also known as tubular locks or "Ace"
locks, were invented in last century and have been developed for
many years. The following U.S. patents are believed to represent
the prior and current state of the art: U.S. Pat. Nos. 4,112,820;
4,621,510, 4,802,354; 5,018,376; 5,400,629; 5,544,512; 6,357,271
and 7,150,168.
As evidenced by these patents, a tubular lock generally includes a
shell containing a plurality of first pin bores; a plug, rotatable
within the shell, containing a plurality of second pin bores facing
to the first pin bores on the shell; and a plurality of pin sets,
each comprising a spring-loaded first pin and a second pin, in the
prior state of the art. The locking mechanism is created by having
each spring-loaded first pin that seated in the first pin bore on
the shell extended into a corresponding second pin bore in the plug
at their initial position so to span both the shell and the plug
and block the plug from rotating. The second pins reside in the
second pin bores in the plug for receiving and transferring
external force and in turn moving their corresponding first pins
away by a pre-determined distance from their initial position so to
catch the shear plane between the shell and the plug. All second
pins normally expose directly to the keyway with relatively bigger
profile so that they are relatively easier to be accessed and
manipulated by picking or bumping tools.
So far as we know, all the development tried to provide a
relatively higher level of security within the prior state of the
art of axial pin tumbler locking mechanism have not changed the
core nature of double-pin-single-spring configuration. So the basic
disadvantage of easily being picked open is not improved
practically.
SUMMARY OF THE INVENTION
It is the primary object of the present invention to provide an
axial pin tumbler lock with a new pin tumbler spring configuration
that is highly resistant to lock picking or bumping attempt.
It is another related object of the present invention to provide an
axial spring balancing pin tumbler lock that is generally cost
efficient to manufacture.
It is a further related object of the present invention to provide
an axial pin tumbler lock that is easy to be assembled, mastered
and serviced.
The foregoing mentioned objects and other objects of the present
invention are achieved by providing an exemplary axial spring
balancing pin tumbler lock with a new and unique pin tumbler spring
configuration that improves the locking mechanism of the prior art
by changing the "initial-on-duty" locking pin tumblers to the
combination pins from the driver pins in the prior art, changing
the driven force that moves the "initial-on-duty" locking pin
tumblers to pre-determined internal forces from external key forces
in the prior art, changing the "initial-on-duty" pins to being
isolated from being exposed directly to the opening keyway in the
prior art. By all those new approaches and more, the axial spring
balancing pin tumbler lock of the present invention makes it
extremely difficult to unlock the lock by means of conventional
lock picking or bumping methods.
Overall, the foregoing objects and other advantages of the present
invention will become more apparent from the following detailed
description when taking in conjunction with the reference
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
The structure, features and functions of this invention are
described in detail with reference to the following description
together with the accompany drawings, in which:
FIG. 1 is a perspective view, quarterly sectioned and broken away,
of an exemplary axial spring balancing pin tumbler lock and a
tubular key of the present invention.
FIG. 2 is an exploded perspective of the lock in accordance with
the present invention.
FIGS. 3a and 3b are isolated perspective views, quarterly sectioned
and broken away and from different angle, of an exemplary housing
used in the lock of the present invention.
FIG. 4a is an isolated perspective view, quarterly sectioned and
broken away, of an exemplary plug used in the lock of the present
invention.
FIG. 4b is a front view, partially sectioned and broken away along
line II-II of the same part in FIG. 4a.
FIG. 5 is a perspective view of a spindle used in the lock of the
present invention.
FIG. 6 is an axially sectioned view showing the locking mechanism
of the present invention in case of no key engaged with the
lock.
FIG. 7 is an axially sectioned view showing the unlocking mechanism
of the present invention when a key with correct notches fully
inserted into the keyway.
FIG. 8 is a perspective view, quarterly sectioned and broken away,
of an exemplary housing sub-assembly used in the lock of the
present invention.
FIG. 9 is a perspective view, quarterly sectioned and broken away,
of an exemplary plug sub-assembly used in the lock of the present
invention.
FIG. 10 is an axially sectioned view of an axial pin tumbler lock
in the prior art.
FIG. 11 is an axially sectioned view showing the picking resistant
features of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
With reference to FIG. 1, an exemplary lock in accordance with the
present invention comprises an axial spring balancing pin tumbler
lock 10 and a tubular key 20 corresponding to the lock 10.
Referring to FIG. 2, the lock 10 comprises a shell 100; a plug 200,
a spindle 300, a plurality of first pins 410 and first coiled
compression spring 420, a plurality of second pins 430 and second
coiled compression spring 440, a plurality of third pins 400, a
retaining pin 480, a cover 500 and a retaining ring 490.
Referring to FIGS. 3a, 3b and 8, the shell 100 comprises a through
hole 101, a main bore 102 coaxially defined on rear end, a shallow
bore 103 coaxially defined on bottom surface 130 of the main bore
102, a first annular groove 104 defined on the through hole 101
near the front end, a second annular groove 107 defined on the main
bore 102 near the rear end, a keyway 105 defined on front end
communicating to the first annular groove 104, and a plurality of
first pin bores 110 defined annularly and evenly along a pitch
circle 120 on the bottom surface 130 of the main bore 102. The
first coiled compression springs 420 and first pins 410 are
disposed into the first pin bores as shown in FIG. 8.
Referring to FIGS. 4a and 4b, the plug 200 comprises a key bore 201
coaxially defined on front end 208, a through aperture 202, a
locking pin hole 204 defined on outer cylindrical surface
communicating to the through aperture 202, an annular collar 205
extended the key bore 201 on front end 208, a plurality of third
pin bores 210 defined on the front end 208 with same depth of the
key bore 201 and arranged such that each one of the third pin bores
210 extends coaxially with one of corresponding first pin bores 110
in the shell 100, a plurality of second pin bores 220, each is
greater than the third pin bore 210 in diameter, defined annularly
and evenly on the rear end 209 and arranged such that each one of
the second pin bore 220 is radially and inwardly eccentric to its
corresponding third pin bore 210 respectively and overlaps the key
bore 201 and one of the corresponding third pin bores 210 radially
and axially in the middle portion of the plug 200.
With reference to FIGS. 5 and 9, an elongated spindle 300 comprises
a front portion 301, a rear portion 302 with smaller diameter than
the front portion 301, a short axial groove 303 defined on the
front end and a cutout 304 defined on the rear portion. The spindle
300 is fixedly engaged with the through aperture 202 in the plug
200 and is secured by a retaining pin 480. The third pins 400 are
disposed into the third pin bores 210 in the plug 200. The second
pins 430 and second coiled compression springs 440 are disposed
into the second pin bores 220 in the plug 200 as shown for
receiving their corresponding third pins 400 and tubular key
notches 203. The cover 500 fixedly attaches to the spindle 300 and
abutted against the rear end 209 of the plug so to retain the
second pins 430 and second coiled compression springs 440 within
the second pin bores 220. The plug sub-assembly 30 is then disposed
into the main bore 102 of the shell 100 in such way that the front
end 208 of the plug 200 mating to the bottom surface 130 of the
shell 100 and is retained by a internal retaining ring 490 so to
prevent the plug sub-assembly 30 from moving outwardly.
Referring to FIGS. 1 and 10, the key 20 used in the present
invention is quite similar to a tubular key 80 in the prior art
except that the key 20 has an elongated tubular portion 201 between
the lug 202 and the notches 203.
The through hole 101 in the shell 100 and the key bore 201 in the
plug 200 have exactly the same diameter. The through hole 101, the
key bore 201 and the spindle 300, when they are assembled,
constitute a tubular keyway 40 for receiving tubular key 20.
Referring to FIGS. 6, 7 and 11, the locking and unlocking mechanism
of an exemplary axial spring balancing pin tumbler lock of the
present invention is described further below.
As has been described in detail in above sections, an exemplary
lock in accordance with the present invention utilizes a plurality
of pin spring set, each comprising three pins 410, 400 and 430 that
are sandwiched between a pair of coiled compression springs 420 and
440 along their pin bores 110, 210 and 220 respectively. Among
those components, the third pin 400 and the first pin 410 have the
same size in diameter so they can slide into each other resident
pin bore in operation. The second pin 430 is greater than first pin
410 in diameter. The extension force of the second coiled
compression spring 440 at its preloaded length is greater than that
of the first coiled compression spring 420 at its fully loaded
length. When there is no key engaged, all second pins 430 and third
pins 400 are urged by the compound extension force of the first
coiled compression springs 420 and the second coiled compression
springs 440 to their most extended position while all first pins
410 are urged to their most retracted position. The third pins 400
are the combination pins of the locking mechanism so their lengths
vary. The shortest third pin 400 is such long that its front end is
flush to the front end 208 of the plug 200 when it is at its most
extended position and the longest is such long that its front end
is flush to the front end 208 of the plug 200 when it is at its
most retracted position. The length varying range of the third pins
400 is defined by the axially overlapped distance 235 of the second
pin bores 220 and the third pin bores 210 in the plug 200. The
mating surface of the plug 200 and the shell 100 constitutes a
shear plane 50 of the locking mechanism of the lock 10 of the
present invention. When there is no key or external picking attempt
engages, all or some of the third pins 400 extend into their
corresponding first pin bores 110 in the shell 100. The extended
third pins 400 bridge the shear plane 50, the plug 200 is therefore
blocked from rotating.
FIG. 7 shows the unlocking mechanism of the present invention in
case that a key 20 with an external key 202, an internal key 204
and the correct notches 203 fully inserted into the keyway 40. Each
notch 203 with correct length properly depresses the second pin 430
away from its initial position and it, in turn, deforms the second
coiled compression spring 440 to such a length that it just allows
the front end of the third pin 400 to coincide with the shear plane
50 by the new compound extension force of the second coiled
compression spring 440 and the first coiled compression spring 420,
the plug 200 is therefore free to rotate within the shell 100.
If a key 20 with incorrect notches 203 is inserted into the keyway
40, the notches 203 and the extension force of the first coiled
compression springs 420 cause the pins 430, 400 and 410 to move
together to such new position that the front end of each third pin
400 is either fallen into the third pin bore 210 in the plug 200,
thus its corresponding first pin 410 will bridge the shear plane
50, or is still remaining in the first pin bore 110 in the shell
100 then the third pin 400 will bridge the shear plane 50. No
matter which scenario occurs, the plug 200 is blocked from rotating
within the shell 100.
With regarding to the picking-resistant features that the present
invention pertains, FIG. 10 to 11 illustrated how it works in some
typical situation of conventional lock picking attempts.
As illustrated in FIG. 10, a conventional pin tumbler lock 60
typically contains only one group of coiled compression springs and
two groups of pins. A group of first pins 720 and first coiled
compression springs 730 reside in a group of first pin bores 710 in
a stationary plug 700 which is fixedly anchored to the shell 600. A
group of second pins 820 reside in a group of second pin bores 810
in a rotatable plug 800 and is partly exposed to the keyway 640.
The first pins 720 are extended into their corresponding second pin
bores 810 in the rotatable plug 800 so to bridge the shear plane 50
and block the rotatable plug 800 from rotating about the stationary
plug 700. To pick a conventional axial pin tumbler lock, it needs
to apply a rotation torque to the rotatable plug 800 first and to
employ a picking tool to tentatively depress a selective second pin
820 and to find a skewed corresponding first pin 720, then further
depress it down until getting a feeling that the other end of the
second pin reaching the shear plane 50. This picking method in the
prior art will not work on this new lock of the present
invention.
As shown in FIG. 11, when a rotation torque 1 is applied to the
spindle 300 then a picking tool 2 is inserted into the keyway 40 to
depress one selected second pin 430 down as it normally does in the
prior art for a picking attempt, the third pin 400 associated with
the second pin 430 will be skewed by the misaligned bores 110 and
210 due to the inevitable tolerance among the components at its
initial position. Depressing or hitting the contacting second pin
430 further by a pick or bumping tool 2 through the keyway 40 will
cause the second pin 430 to be separated from its mating third pin
400 and a gap 4 will be produced. Since the third pin 400 is
isolated from the keyway 40, there is no way to pull or push the
third pin 400 moving back to the third pin bore 210 except with the
extension force of the first coiled compression spring 420.
However, that force is too small to overcome the pin skewing
friction. A sudden release of the rotation torque 1 may help the
skewed third pin 400 moving, but the moving distance is not
controllable, and the picking or bumping attempts must fail.
As shown in FIG. 11, an exemplary lock of the present invention has
a coupling arrangement: an annular collar 205 defined on front end
208 of the plug 200 mates a shallow bore 103 coaxially defined on
the bottom surface 130 of the main bore 102 in the shell 100. This
structure constitutes two straight angle turns about the tubular
keyway 40 so to prevent the third pins 400 from being accessed or
measured by a picking tool.
* * * * *